April 20 Activities
S/E- science and engineering combined! As spring unfolds, we notice a lot of snow melting. When snow melts, it becomes water, and due to gravity, joins rivers and streams in what we call “runoff.” Many people use runoff to water fields, gardens, or livestock. What if we had to drink it? Do you think it would be healthy? Probably not! There are millions of tiny (so tiny we can’t see them = “microscopic”) plants and animals living in runoff that could make us sick! But what if we had no choice? We would have to filter (strain out) those microscopic things out of the water to make it safer. Let’s do that together! If you have one, start with a large pop or juice bottle*. Cut the top off and drill holes in the bottom of the bottle (with parents’ help), and use things like paper towels, gravel, sand, coffee filters, even socks (CLEAN ONES) to make several layers (try two layers to start with, and if you have time, try again with three, four or more layers!) of filtering materials. This way, you should end up with a filter with an opening at the top to pour the water into, layers of filtering materials in the middle, and some holes in the bottom to let the cleaner, filtered water out. Make sure you also have a cup or bowl to catch the water at the bottom of your filter. To make your “dirty water,” use a fixed amount of water (for example, one cup) and add a fixed amount (for example, a tablespoon) of dirt or sand or sawdust to represent our microscopic water organisms. Mix whatever you’ve added to the water in thoroughly, and pour slowly through your water filter (probably best with parents’ help). Remember, you will need a clean cup or bowl at the bottom of your filter to catch the cleaned water as it is filtered through! As the water drains out of the bottom, you can check to see if it looks cleaner than it did when you poured it in! Next, after all the water has drained through, gently pull your layers of filtering materials out to see how well each layer filtered the dirt from your dirty water. Which layer caught the most dirt?
BONUS: Save that first cup of filtered water to compare with the next filter you build! If you have time, try building two or three different filter designs (try changing filter materials, the order in which the layers are stacked, the number of layers, or the number of holes drilled into the bottom) to determine which one filters the most dirt out of your water samples, and leaves your water cleanest at the end. IMPORTANT: make sure you’re using the same amount of water and the same amount (and type) of contaminants to run through each filter!
*If you don’t have a large plastic bottle, try a coffee can (or other large plastic container), or even a plastic bag (best if supervised and taped to the side of a bathtub or deep sink).
T/M- technology/math combined! If you had a castle, long ago, chances are you’d also have had a catapult. Catapults are tools that use some super easy physics to launch heavy objects a really long way. We will be looking at how they work, and building a much smaller and friendlier version with stuff you can find around your house*. Once your catapult is built, you will want to find some things to send flying. Do this with PARENT PERMISSION and keep the following safety rules in mind: do not fire at ANY person or living thing, use this outdoors only, do not fire at anything that could be breakable, and do not use anything hard or breakable to launch. Stick with soft projectiles (things that fly through the air), like cotton balls, balls of paper or tape, or other soft things you can find outside or around your house. Once you have picked a soft projectile, grab a piece of paper and a pencil, head outside, and launch it from a set spot on the ground (mark this with tape or a pebble or something so you fire from the same spot every time). Measure how far your soft projectile went (if you don’t have a tape measure, count how many steps it takes you to get to the thing you shot) and write it down as “Test #1.” Try it again, measure, and record it as “Test #2.” Do some math! Did Test #1 go further than Test #2? If so, how much further did it go? Find the difference (subtract the smaller number from the bigger number). Try a few more tests with the same soft projectile. If you want to go a step further (and who wouldn’t, with a homemade catapult?), find a second soft projectile. Fire that, measure it, record it as “Projectile 2, Test #1” and repeat. Find out if projectile 1 or 2 went farther, and how much farther?
Please continue to take photos of your catapults (and any other projects you’ve done) and your test results and send them to me! I’d love to see your success!